Heavy petroleum residues resulting from the crude oil refining industry have been treated to recover nondistillable oils by conventional solvent extraction and, more recently, by an energy-efficient process called the ROSE process (Residuum Oil Supercritical Extraction). The ROSE process is an energy-efficient solvent extraction process developed by Kerr-McGee Refining Corporation for upgrading heavy crudes and residuals. In accordance with the ROSE process, asphaltenes, resins and oils can be separated and the solvent recovered without using traditional vaporization and liquification steps thereby substantially reducing the energy requirements to recover the recyclable solvent. The ROSE process is described in a brochure entitled "ULTIMATE UTILIZATION OF FCC CAPACITY WITH THE ROSE .RTM. PROCESS, by W.L. Vermilion and J.A. Gearhart presented at the Katalistiks' 4th Annual Fluid Cat Cracking Symposium May 18-19, 1983 Amsterdam, The Netherlands.
In accordance with this ROSE process, one of the separated fractions from the residuum oil is a liquid asphaltene recovered from a flash tower where solvent is flashed away from the liquid asphaltene product.
Until recently, this asphaltene product presented a serious environmental problem since it was a waste product and very costly to transport and bury in a land fill. More recently, others have taken the hot liquid asphaltenes and spread them as a film on a cooled belt to solidify the material. The solidified asphaltene, as a thin flake, then was ground to a powder for use in asphalt road paving and the like. This method of recovering the asphaltenes in the form of a flat solid flake thereafter ground to a fine powder has produced many problems, particularly the creation of large quantities of dust when the flake is broken into a grindable size and in handling problems of the fine powder after grinding.
In accordance with the present invention, the liquid asphaltene material is flowed by gravity through a flow channel downwardly in the form of an annular elongated stream into a reservoir of cooling liquid to cause solidification and shattering of the liquid stream into pellets of relatively uniform particle size. The pellets are recovered from the water in relatively dustless form and any solid fines can be recirculated to a liquid asphalt reservoir for reliquification.